Flexible printing stock is commonly supplied in the form of rolls formed around a cylindrical core. The flexible stock supplied on these rolls can be dispensed from the core while the core is supported by a horizontal shaft. While so supported, the roll can move axially with respect to the shaft, thereby causing problems if the flexible stock is being fed to a machine having low tolerance to printing stock misalignments. Many types of printers have a low tolerance to such misalignments.
In order to overcome the alignment problem, it is possible to closely confine the axial movement of the core carrying the flexible stock by mechanically defining axial limits outside which the flexible stock core will not be allowed to pass. Such a method works adequately if the width of the rolls of flexible stock is substantially constant. However, if it is possible that the flexible stock can be supplied on any of a number of standard roll widths, either a number of shafts, one for each of the standard widths, must be supplied or else the axial end limits must be discretely adjustable.
In situations where, for example, the roll can come in random widths or the position of the roll on the shaft must be continuously adjustable, such approaches are of no avail.
Prior art solutions to the variable-width label stock problem have used a collet in conjunction with an internally threaded screw-on nut to clamp the collet in place. A collet-clamp fitting of this type is difficult to manufacture because it is necessary to machine the threads on the outer surface of the collet and on the inner surface of the nut. Further, in order to prevent the collet and nut from being separated once assembled, assembly requires the inclusion of a stop device. The likelihood that the collet and the nut could become separated is increased where, as in the prior art, the collet and clamp nut can be disassembled by twisting them in the same relative directions as is required to loosen the collet-nut fitting.